Assessing Standard of Care in Polypharmacy: Triable Issues in Sweeney v. Niagara Lutheran Development

Introduction

This commentary reviews the Appellate Division’s March 21, 2025 decision in Sweeney v. Niagara Lutheran Development, Inc. The case arises from a medical malpractice and wrongful death suit filed by the administrator of Marie Sweeney’s estate against her treating physician, Dr. Patrick Siaw, and the nursing home facility (Greenfield Health & Rehabilitation Center) and its parent corporation (Niagara Lutheran Health System). At issue was whether Dr. Siaw’s decision to prescribe baclofen in conjunction with the opioid‐based pain reliever Norco deviated from the accepted standard of care and whether Greenfield or Niagara could be held vicariously liable for Dr. Siaw’s alleged negligence.

Key issues:

Did prescribing baclofen together with Norco breach the medical standard of care?
Was any such alleged deviation a proximate cause of the decedent’s injuries and death?
Can the nursing home or its corporate parent be held vicariously or ostensible‐agency liable for Dr. Siaw’s conduct?

Parties:

Plaintiff‐Respondent‐Appellant: Michael Sweeney, as Administrator of the Estate of Marie Sweeney
Defendant‐Appellant‐Respondent: Patrick Siaw, M.D.
Defendants‐Respondents: Niagara Lutheran Development, Inc. (Greenfield) and Niagara Lutheran Health System, Inc.

Summary of the Judgment

The Fourth Department unanimously affirmed the trial court’s order in part and reversed in part:

It denied Dr. Siaw’s motion for summary judgment, finding that plaintiff’s experts had raised triable issues of fact as to breach of care and proximate cause when prescribing baclofen with Norco.
It granted Greenfield’s and Niagara’s motion for summary judgment, concluding that plaintiff failed to establish any genuine issue of fact as to an employer‐employee relationship or ostensible agency.
It also affirmed the court’s discretionary allowance of late‐filed expert curricula vitae and related record‐settling motions.

Analysis

1. Precedents Cited

Occhino v. Fan (151 AD3d 1870): Burden‐shifting framework in medical malpractice summary judgment—initial burden on defendant to show no breach or causation; then burden shifts to plaintiff to raise triable issues.
Lewis v. Sulaiman (217 AD3d 1443): Clarifies that once a defendant meets the prima facie burden, plaintiff need only dispute those specific elements.
Leberman v. Glick (207 AD3d 1203) and Wilk v. James (107 AD3d 1480): Expert opinions creating factual disputes on breach and causation defeat summary judgment.
Cooke v. Corning Hosp. (198 AD3d 1382) and Peevey v. Unity Health Sys. (196 AD3d 1139): “Battle of the experts” cases are for the jury when opinions directly conflict.
Pasek v. Catholic Health Sys. (195 AD3d 1381) and Mduba v. Benedictine Hosp. (52 AD2d 450): Standards for vicarious liability and ostensible agency in healthcare settings.

2. Legal Reasoning

a. Summary Judgment Burden Framework
Under New York law, a defendant physician must first show either no deviation from the standard of care or no causal link. Once met, the plaintiff must identify an expert affidavit raising a triable issue on breach or causation (Occhino, Lewis).

b. Expert Affidavits on Polypharmacy Risks
Plaintiff’s two experts—one in geriatrics/internal medicine and one neurologist—opined that prescribing baclofen with Norco posed a “moderate contraindication” and was outside the standard of care, and that the resulting metabolic encephalopathy and prolonged supine positioning led to pneumonia and septic shock. Dr. Siaw’s expert contested these opinions. The court held that these directly opposing views created a classic jury question (Cooke).

c. Vicarious Liability & Ostensible Agency
Greenfield and Niagara demonstrated that Dr. Siaw was neither their employee nor under their operational control, negating a respondeat superior claim. They further showed that the decedent could not have reasonably believed they had chosen or supervised Dr. Siaw, defeating ostensible agency (Pasek, Mduba).

d. Record‐Settlement Discretion
The court’s acceptance of late‐filed expert CVs was a proper exercise of discretion, given law office failure and the preference for merits decisions (Fuller v. Aberdale, Payne v. Buffalo Gen. Hosp.).

3. Impact

This decision reinforces several important principles:

In medical malpractice matters involving polypharmacy, expert testimony on drug interactions can alone generate triable issues, preventing premature summary judgment.
The “battle of the experts” remains a recognized standard—courts should not weigh competing expert opinions at the summary stage.
Healthcare facilities will find it difficult to attach vicarious liability absent clear employment or control, and ostensible agency claims require more than passive association.
Procedural leniency in accepting late expert credentials underscores New York’s preference for adjudicating cases on substantive grounds.

Complex Concepts Simplified

Standard of Care: The degree of skill and diligence that a reasonably competent professional would exercise under similar circumstances.
Prima Facie Burden: The initial showing of facts sufficient to support a legal claim, shifting the burden to the opposing party.
Proximate Cause: A legal cause that is sufficiently related to the injury; without it, liability cannot attach.
Summary Judgment: A court’s decision to resolve a case without a full trial when there is no genuine dispute of material fact.
Vicarious Liability (Respondeat Superior): Holding an employer liable for the torts of an employee committed within the scope of employment.
Ostensible Agency: A theory by which a principal is held liable for an agent’s acts if a third party reasonably believes the agent is authorized and the principal acquiesces.
Battle of the Experts: When each side presents expert opinion evidence on the same issue, creating a factual dispute for jurors to decide.

Conclusion

Sweeney v. Niagara Lutheran Development clarifies that in polypharmacy‐related malpractice suits, conflicting expert testimony on drug interactions inherently precludes summary judgment. It affirms the “battle of experts” doctrine, mandates rigorous application of burden‐shifting rules, and delineates strict limits on institutional liability absent employment or valid ostensible agency. By emphasizing resolution on the merits and preserving jury fact‐finding, this decision strengthens procedural fairness and sets a guiding precedent for future medical negligence and agency disputes in New York.